Dual lag screw anchoring insert for a concrete slab



Jilly 20, 1965 H. a. BALLOU mm. me SCREW ANCHORING msnnr FOR A CONCRETESLAB Filed llay 7, 1962 2 Sheets-Sheet 1 liar 3 6- 6 li njj" July- 20,1965 Filed May 7. 1962 H. a. BALLOU 3,195,278

DUAL LAG SCREW ANCHORING INSERT FOR A CONCRETE SLAB 2 Sheets-Sheet 2Irzflrzfw: 17271} 6: [1064.

United States Patent ration of Delaware Filed May 7, 1962, Ser. No.192,771 1 Claim. (Cl. 50-472) The improved anchoring insert comprisingthe present invention has been designed for use primarily in connectionwith concrete wall slabs of the tilt-up type wherein the insert which isformed for the most part of heavy wire or rod stock is adapted to beembedded in one corner portion of a wall slab during formation of thelatter, and serves, with similar inserts in the other corner portions ofthe slab and after hardening of the concrete, as a medium whereby theslab may be detachably connected to a crane or like hoisting mechanismto the end that the slab may be first raised while in a horizontalposition and then tilted into a vertical position next to a concretefloor slab in connection with the erection of a building. The inventionis, however, not to be limited to such particular use, and a wire-formedinsert which is constructed according to the principles of the presentinvention may find use wherever an anchor point is required in aconcrete structure undergoing formation. Irrespective, however, of theparticular use to which the invention may be put, the essential featuresthereof are at all times preserved.

As disclosed in United States Patent No. 2,794,336, granted on June 4,1957, and entitled Lag Screw Anchoring Insert for a Concrete Slab, adual lag screw anchoring insert of the general character with which thepresent invention is concerned includes as its principal components apair of spaced apart, nut-like, wire-formed helices to which there iswelded a wire supporting structure presenting a series of supportinglegs whereby the helices are adapted to be supported from a foundationsurface so that they assume elevated positions above such foundationsurface, the entire assembly assuming the general form of a chair. Whenthe slab or structure-forming concrete is poured, the chair-like insertbecomes embedded in the concrete and the helices assume positions atright angles to the upper surface of the poured slab and with theirupper ends substantially flush with said surface to the end that theymay receive therein the shank portions of lag screws or other attachingdevices. The present invention is designed as an improvement over thedual lag screw anchoring insert which is illustrated and described inthe aforementioned patent in that it offers several advantagesthereover.

When lifting stresses are applied to an anchoring insert of the typewith which the present invention is concerned in order to raise theassociated slab, there is a tendency for the insert to pull out of theconcrete. This is particularly true where the concrete of the slab hasnot fully hardened or become set. Subsequently, when tilting operationsare in progress whereby the slab is turned on edge and placed against afloor slab, considerable torque is developed and applied to theanchoring helices by the lag screws which are received therein, thuscreating a tendency for the helices to become angularly displaced. Forthese reasons, the aforementioned wire-supporting structure which isassociated with the helices invariably involves outrigger devices in theform of wire loops, transverse rods and other projecting parts which arewelded to the helixes and to one another, extend in various directionsand are calculated to establish the necessary reaction forces to preventdisplacement of the helices from their fixed positions of embedment inthe concrete slab. The dual lag screw anchoring insert of the presentinvention offers a more efficient arrangement of such outrigger devicesthan is present in connection with conventional anchoring insertsincluding the insert of aforementioned Patent No. 2,794,336, bothagainst angular shifting of the helices and against upward or axialpulling of the helices through the slab. It also offers a structurewhich, when in position within the slab form preparatory to concretepouring operations, offers a greater reaction area within the concretewhile at the same time offering a definite economic advantage inasmuchas an appreciable portion of the insert is made up of scrap reinforcingrod Which is to be found in large quantity at the scene of any largescale building operation and, therefore, need not be furnished as acomponent part of the manufactured insert. Because of the fact that anappreciable portion of the insert is not a part of the manufactureditem, less storage space is required for the inserts when shipped inquantity and freight charges are proportionately reduced.

Another advantage that accrues from the present invention resides in thefact that whereas with a conventional anchoring insert the supportingstructure for the helices must be itself supported from the floor slabor other foundation surface so that in the completed slab there areportions of the structure which are exposed or nearly exposed at thesurface of the slab, in the present insert the supporting structure, andconsequently, the entire insert, may conveniently be supported in anelevated position above the foundation surface so that, after the slabis formed, the insert as a whole is disposed well within the confines ofthe slab and away from the top and bottom surfaces thereof. Thisadvantage of the invention is made possible by a novel saddlearrangement which is inherent in the supporting structure for thehelices and by which the supporting structure is itself supported on thereinforcing bars which ordinarily are associated with tiltup and othertypes of slabs.

The attainment of the above-outlined advantages of the present dual lagscrew anchoring insert constitutes the principal objects of the presentinvention and other objects and advantages will readily suggestthemselves as the following description ensues.

In the accompanying two sheets of drawings forming a part of thisspecification, one illustrative embodiment of the invention has beenshown.

In these drawings:

FIG. 1 is a perspective view of a dual lag screw anchoring insertconstructed in accordance with the principles of the present invention;

FIG. 2 is an enlarged fragmentary side elevational view of one side orsection of the insert;

FIG. 3 is a top plan view of the structure shown in FIG. 2;

FIG. 4 is an end view of the structure shown in FIG. 2;

FIG. 5 is a fragmentary vertical sectional view taken through a tilt-uptype concrete wall slab in the vicinity of two embedded anchoringinserts, showing the slab within a slab form and also showing, in dottedlines, the slab after it has been connected to a harness on a crane oroverhead hoist; and

FIG. 6 is a fragmentary top plan view of a slab form showing a number ofthe anchoring inserts operatively installed therein prior to a concretepouring operatic-n.

Referring now to the drawings in detail, the anchoring insert which isdisclosed therein constitutes a preferred form or embodiment of theinvention and is designated by the reference numeral 10. This insert isadapted, with similar inserts, to be embedded in a tilt-up type concretewall slab such as the slab which is fragmentarily shown at 12 in FIG. 5and to form with such inserts a medium whereby the slab may bedetachably connected to a crane or other overhead hoist to the end thatit may be raised, and then tilted into a vertical position next to aconcrete 3 r g floor slab in connection with the construction of aconcrete building.

Insofar as the actual handling of the slab is concerned,

1 various methods of raising the same and then tilting it are clurrentlyin use. For a better understanding of the present invention, referencemay be had to aforementioned Patent No. 2,794,336 for one exemplarymethod of handling the slab. Briefly, and as generally described in suchpatent, the wall slab is formed by pouring wet or fresh concrete overthe surface of a previously cast floor slab 14 and within a slab formconsisting of form boards 15. A layer or film of nonadhesive material isapplied to the top surface of the concrete floor slab'ld so that theconcrete for the wall slab 12, when hardened, may readily be lifted fromthe floor slab for placement or positioning purposes. The floor slab 14-rests on a fill or foundation 16 at the site where the building isundergoing erection. Prior to pouring of the concrete to form the wallslab 12, the anchoring insert 19 and its associated similar inserts areplaced over the hardened concrete of the floor slab 14, preferably atthe corner regions thereof, and the concrete is then poured within theform to form the wall slab 112..

As will be described in greater detail hereafter, such positioning ofthe insertsover the floor slab 14, according to the present invention,is accomplished by supporting the inserts upon previously positionedreinforcing rods which are an attribute of conventional tilt-up slabs,so that the insert will lie well within the physical confines of theslab form and be appreciably removed from-surface exposure in thecompleted wall slab. When the inserts are in position within the wallform concrete is then poured within the form boards in order to form thewall slab 12. After the concrete has hardened and the form boards havebeen removed, the wall slab 12 with the anchoring inserts 1t embeddedtherein is in readiness to be raised and subsequently tilted into avertical position next to the floor slab 14 as hereinafter described.

The anchoring insert 10 is of a composite nature but, nevertheless, itis a unitary structure and for the purpose of the following description,it will be considered as being embedded in one corner region of the wallslab 12 while the latter. is horizontally positioned over the concretefloor slab 14'. As its principal components, the insert 1%) comprises apair of nut-like wire helices 3t and 31 and a supporting structure 32.The structure 32 is common to the two helices and is provided for thedual purpose of providing a reaction thrust against the tendency of thehelices to work loose in the concrete bond after the concrete of theslab has been poured and has become hardened and when lifting thrust isapplied to the lag screws which are threaded into the helices, and ofsupporting the helices in their elevated spaced apart positions withinthe slab form.

The supporting structure 32 is comprised of four wireforrned parts,namely, a pair of generally horizontally extending combined saddle andcradle parts 34 and 36, and a pair of wire-formed wing parts 38 and 4The saddle and cradle parts 34 and 36 are common to and extend betweenthe helices 3t and 31, while the wing parts 38 and 4t? are individual tothe .helices 3t and 31, respectively.

The saddle and cradle parts 34 and 36 are similar in their constructionand each is in the form of an elongated length of relatively heavy wirestock which is bent so as to provide an elongated and straight medialsection 42, a

pair of upwardly presented, U-shaped cradle portions id, and a pair ofvertical legs 46 at the outer sides of the -of the elongated dual lagscrew anchoring insert 18.

A to receive loosely therein a pairof horizontally extending anchor bars54 in a manner and for a purpose that will be made clear presently.The'two saddle and cradle parts 34 and 36 extend generally inparallelism longitudinally The outside vertical legs 46 are offsetinwardly from the vertical planes of the medial, sections 42 so that thedistance between adjacent vertical legs 46 is less than a helixdiameter, while the distance betwen the two medial sections of thesaddle and cradle parts 34 and as is greater than helix 30 at regionswhich are spaced fairly widely apart,

this arrangement being best illustrated in FIG-3.

The adjacent U-shaped cradle portions 44 of the saddle and cradle parts34 and 36 lie in vertical planes which extend at an angle ofapproximately 60 to each other as shown in FIG. 3. The depth of thesecradle portions is approximately equal to the vertical depthof the wingparts 38 and 44), which is to say that the lower parts of the cradleportions and wing parts all terminate in substantially the samehorizontal plane. The triangular portions of the wing parts 34 and 36lie in planes which are inclined outwardly and downwardly away from thevertical axes of the helices 3t) and 31at angles of approximately 30.

As shown in full lines in FIGS. 5 and 6 and as heretofore indicated, thedual lag screwanchoring insert 19 is adapted to be supported within onecorner portion of a rectangular form which is defined by the form boards15. The two horizontally extending medial sections 42 of the saddle andcradle parts. 34 and 36 are adapted to be supported upon adjacentparallelspaced apart rein forcing rods 52, such rods being shown indotted lines in FIGS. 2 and 3 of the drawings and in full lines in FIG.6. The distance between the vertical legs 50 at the ends of these medialsections 42 is slightly greater than the spacing of the reinforcing rods52 so that the saddle-like central region of the insert 10 may seat uponthe reinforcing. rods with but little end play longitudinally of theinsert, and-so that ,by merely positioning the insert 10 on the rods 52,proper alignment of the insert will automatically take place. When thusin position on the rods 52, the lower ends of the cradle portions 44 .aswell as the lower ends of the Wing parts 38 and 40 will be positioned aslight distance above the upper face 70 of the floor slab 14 which, ineffect, constitutes the bottom wall of the form for the wall "slab 12.Stated otherwise, the entire insert 10 will be suspended an appreciabledistance above the surface 70 so that in the finished wall slab 12, theinsert 10 will be more or less centered between the upper and lowerfaces '72 and 74 of the wall slab.

It-will be understood that three other anchoring inserts 10 will bepositioned in the form for ultimate embedment in three other corners ofthe wall slab 12.

After the insert it) is in position within the form as heretoforedescribed, the anchor bars 54. are loosely positioned within the cradleportions 44 of the combined saddle and cradle parts 34 and 36,and whenso positioned within said cradle portions, these anchor bars increasethe effectiveness of the inserts. While'the manufacturer of theanchoring insert, may, if desired, furnish suitable anchor bars for useat the scene of operations, ordinarily such bars will not be furnishedand the contractor or consumer may rely for these bars upon theexistence of scrap reinforcing rods, of which'there invariably is alarge quantity in and around theiscene of any large-scale buildingoperation. The length of the anchor bars 54 is not critical, and bars ofvarying lengths which are suitable for use may be found at the scene ofoperations and placed within the cradle portions 44 without furtherattention. If suitable lengths are not available, it is a comparativelyeasy matter to saw an elongated length of the reinforcing rod stock toform the anchor bars. It is to be particularly noted that because of thelocation or position of the bottom parts of the cradle portions 44 withrespect to the lower face 74 of the wall slab 12, there is a maximumamount of concrete above the anchor bars. As theresult of this, theinsert is effetcively held in place in the wall seat and will not pullout even though the slab is raised while the concrete is in a green orpartially set condition.

After the wet concrete for the wall slab 12 has been poured, suitablestrickling operations utilizing a screed are performed upon the uppersurface of the concrete in order to produce the fiat upper face 72. Whenthe concrete of the wall slab 12 has become set to a suitable degree,the form boards 15 are removed, and in order that the wall slab 12 maybe hoisted from its horizontal position on the floor slab 14 and thentilted into a vertical. position for Wall-forming purposes as previouslydescribed, lag screws such as have been shown at '75 in FIG. 5 arethreaded into the helices and 31 and constitute media whereby the wallslab 12 may be detachably connected to a crane or other overhead hoist.

Still considering the wall slab 12 to be in its horizontal position onthe floor slab 14 preparatory to hoisting operations, the lag screwspass through the then horizontal flange 7e of an elongated angle piece78 and serve to clamp this angle piece hard against the upper face 72 ofthe wall slab 12. The vertical flange 80 of the angle piece is providedwith a hole 82 therethrough and receives the shank portion of an eyebolt 84, the latter being operatively connected to one of the cables 86of a hoisting harness in associated relation with the crane or otheroverhead hoist. The details of the hoisting harness have not beendisclosed herein since the harness forms no part of the presentinvention. It is deemed sufficient to state that the cable 86 passesloosely over a sheave 88 and that the opposite ends of the cable 86 areconnected in a manner previously described to another dual anchoringinsert 10 in an opposite corner region of the slab 12.

The specific manner in which the slab 12 is first hoisted verticallyfrom its horizontal position and then tilted into position against thefloor slab 12 has been disclosed in the aforementioned Patent No.2,794,336 and need not be described herein. However, for illustrativepurposes, the dotted line disclosure of FIG. 5 shows the elevated slabimmediately prior to the tilting process. It will be observed that whenthe stress upon the helices 30 and 31 is vertical, as, for example,during lifting of the slab 12 from the floor slab 14- upon which it isformed, the helices will find adequate support in the concrete on bothsides thereof in the longitudinal direction of the insert. The spread ofthe wing parts 38 and 40 outwardly and downwardly in the corner regionsof the slab 12 gives good support to the remote or outer sides of thetwo helices, while the two combined saddle and cradle parts 3 5 and 36,together with the anchor bars 54, afford good reaction for the helicesat the inner or opposed sides thereof. As the slab is tilted preparatoryto fitting the same against the floor slab in a vertical position, thelateral stresses which are applied to the two helices 3t) and 31 areassimilated in approximately equal degrees by the wing parts 38 and 40and the combined saddle and cradle parts 34 and 36.

The invention is not to be understood as restricted to the details setforth since these may be modified within the scope of the appended claimwithout departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

As a new article of manufacture, a dual lag screw anchoring insertadapted for initial positioning in a concrete slab form and ultimateembedment in the concrete slab, and adapted to form an anchor for a pairof lag screws, said insert comprising a pair of wire helices disposed inspaced apart relation and adapted to have their axes extend verticallywith their upper ends disposed directly inwards of and opening onto theupper face of the slab when the latter is in the horizontal position inwhich it is cast, the interiors of said helices forming internalscrew'threads for receiving the shank portions of the lag screws, and asupporting structure for said helices whereby the same may be supportedin their spaced relation from a pair of adjacent parallel horizontallyextending reinforcing rods pre-positioned in the form, said supportingstructure including two spaced apart, generally parallel, lengths ofwire stock, each length having an elongated horizontal medial sectionmidway between the vertical axes of the helices and below the level ofsaid helices and constituting a major portion of the length, anddownwardly extending bight portions at the opposite ends of the medialsection and providing upwardly presented open cradle portions adjacentto the helices respectively, adjacent bight portions lying in respectivevertical planes which are disposed at an angle of approximately 60 withrespect to each other, said horizontal medial sections of the twolengths of wire stock, in combination with the adjacent sides of thebight portions, constituting a saddle for reception over said pair ofreinforcing rods whereby the anchoring insert is supported solely bysuch rods, adjacent cradle portions being adapted loosely to receivetherein in horizontal supporting relationship an elongated anchor bar,the sides of said bight portions remote from the medial sections beingwelded to the outside surfaces of the helices respectively, the upperends of said remote sides of the bight portions projecting upwardlyabove the level of the medial sections and above the open upper ends ofthe cradle portions, said anchoring insert further including a pair ofwing parts, one for each helix, each wing part being in the form of alength of wire stock bent into substantially triangular loop form so asto provide a horizontal base with upwardly converging sides, the upperends of said latter sides being provided with vertical extensions whichare welded to the outer side of the adjacent helices.

References Qited by the Exaer UNITED STATES PATENTS 1,139,987 5/15Lukens 50-517 1,817,059 8/31 Bitney 50-517 2,345,976 8/44 Hillberg50-517 2,794,336 6/57 Ballou 50-474 FRANK L. ABBOTT, Primary Examiner.

JACOB L. NACKENOFF, BENJAMIN BENDETT,

Examiners.

